With the rapid development of high speed railway and expressway, a future mobile communication system faces more and more high-speed moving environments, which require the communication system to support a higher moving speed. Correspondingly, Long Term Evolution (LTE) optimizes a low-speed moving scenario of 0˜15 km/h for User Equipment (UE), ensures that the high performance of the communication system can be achieved for the UE in a high-speed moving scenario of 15˜120 km/h, and ensures that the mobility of a cellular network can be kept for the UE in a high-speed moving scenario of 120˜350 km/h (even 500 km/h is supported in some frequency bands).
For meeting a system bandwidth requirement of 100 MHz of the International Mobile Telecommunications-Advanced (IMT-Advanced), the 3rd Generation Partnership Project (3GPP) LTE Release 10 introduces a Carrier Aggregation (CA) technology. Wireless transmission characteristics, such as wireless propagation path loss and Doppler frequency shift, of different component carriers are different, and a proportional fair allocation policy exists, therefore, when a component carrier is allocated for UEs in the cell, the component carrier is always preferentially allocated for the UE which has high throughput and moves at a low speed in the cell, which causes the poor communication quality of the UE which has a low throughput and moves at a high speed, thereby affecting the user experience.